Return-Path: Received: (qmail 8097 invoked from network); 14 Jan 2005 11:58:13 -0000 Received: from unknown (HELO ptb-spamcore02.plus.net) (192.168.71.3) by ptb-mailstore01.plus.net with SMTP; 14 Jan 2005 11:58:13 -0000 Received: from mailnull by ptb-spamcore02.plus.net with spamcore-l-b (Exim 4.32; FreeBSD) id 1CpPxH-0008Dm-9e for dave@picks.force9.co.uk; Fri, 14 Jan 2005 11:51:39 +0000 Received: from [192.168.67.2] (helo=ptb-mxcore02.plus.net) by ptb-spamcore02.plus.net with esmtp (Exim 4.32; FreeBSD) id 1CpPK6-0004Vq-Mo for dave@picks.force9.co.uk; Fri, 14 Jan 2005 11:09:55 +0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore02.plus.net with esmtp (Exim) id 1CpPNU-000PEr-58 for dave@picks.force9.co.uk; Fri, 14 Jan 2005 11:12:28 +0000 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1CpPL0-00053m-Fc for rs_out_1@blacksheep.org; Fri, 14 Jan 2005 11:09:54 +0000 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1CpPKx-00053d-QL for rsgb_lf_group@blacksheep.org; Fri, 14 Jan 2005 11:09:51 +0000 Received: from mout1.freenet.de ([194.97.50.132]) by relay.thorcom.net with esmtp (Exim 4.43) id 1CpPKu-0006nA-6Z for rsgb_lf_group@blacksheep.org; Fri, 14 Jan 2005 11:09:51 +0000 Received: from [194.97.50.138] (helo=mx0.freenet.de) by mout1.freenet.de with esmtpa (Exim 4.46) id 1CpPKa-0003fn-4F for rsgb_lf_group@blacksheep.org; Fri, 14 Jan 2005 12:09:28 +0100 Received: from www9.emo.freenet-rz.de ([194.97.107.202]) by mx0.freenet.de with esmtp (Exim 4.43 #13) id 1CpPKa-0001P7-3F for rsgb_lf_group@blacksheep.org; Fri, 14 Jan 2005 12:09:28 +0100 Received: from www-data by www9.emo.freenet-rz.de with local (Exim 4.34 1 (Panther_1)) id 1CpPKZ-0001YH-2V for ; Fri, 14 Jan 2005 12:09:27 +0100 To: rsgb_lf_group@blacksheep.org From: dl4yhf@freenet.de X-Priority: 3 X-Abuse: 505770703 / 213.182.113.58 MIME-Version: 1.0 Message-Id: Date: Fri, 14 Jan 2005 12:09:27 +0100 X-Warning: freenet.de is listed at abuse.rfc-ignorant.org X-SPF-Result: relay.thorcom.net: 194.97.50.132 is neither permitted nor denied by domain of freenet.de X-Spam-Score: 1.9 (+) X-Spam-Report: autolearn=no,HTML_20_30=0.504,HTML_MESSAGE=0.001,NO_REAL_NAME=0.178,PRIORITY_NO_NAME=1.185 Subject: Re: Re: LF: Simple image-cancelling exciter for digimodes Content-Type: text/html; charset=windows-1252 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.1 required=5.0 tests=HTML_MESSAGE,NO_REAL_NAME, PRIORITY_NO_NAME autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Spam-Filtered: by PlusNet SpamCORE (v3.00) Content-transfer-encoding: 8bit MessageHi Stewart,

Thanks for the suggestion - sounds too good to be true !
(to build an image-cancelling "TX"-mixer without the need for a phase-split audio if I understand you correctly).

I must admit I blindly followed the ARRL handbook which seemed to imply "you cannot build an image-cancelling mixer without some phase shifting on the low-frequency side" (unless you use the "weaver" method with pilot tones).

I have some old CMOS 4052 somewhere (not 74HC...) so may try these.
When using std CMOS in my "conventional" prototype, the sideband-suppression was worse than with the 74HCxxx because they were too slow, and the L.O. outputs were not symmetrically enough.


Will let you know about any progress with this.
At the moment  I'm quite happy with my old design which still waits to be connected to an amplifier for an on-air test (but that won't be before next weekend).


Best regards,
Wolf DL4YHF .




--- original Nachricht Ende ----


Hi,

You may wish to consider a dual 4-input analog mux such as
the '4052. For instance, see
http://www.semiconductors.philips.com/pip/74HC4052.html

You can connect the quadrature LO outputs directly
to the S1 and S0 inputs. Then, because there are two
muxes, you can create a differential output without
needing to phase-split the incoming audio.

For example, assuming address sequence is 0-1-3-2-0-1-3-2
(S1 lags S0) connect:

1Y0=Left ch.
1Y1=Right ch.
1Y2=GND
1Y3=GND

2Y0=GND
2Y1=GND
2Y2=Right ch.
2Y3=Left ch.

Then, the voltage between 1Z and 2Z is the SSB output.

Perhaps, you can use a transformer-coupled output.
Put a cap across the primary to resonate at the
approximate output frequency, and connect it from 1Z to 2Z
through a suitable resistor. No op-amps or precise
resistors needed, and it provides the first stage of
filtering.

Disclaimer: I have not tried this, and there may be
a stupid reason why it won't work. Please don't
laugh too hard.

73,

Stewart KK7KA



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